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in  2010  witii  funding  from 

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http://www.archive.org/details/porcelaininlaytrOOpeck 


PORCELAIN  INLAY 


A  TREATISE  ON  ITS 
THEORY  AND  PRAC- 
TICE  IN    DENTISTRY 


«|y  ARTHUR  E.  PECK,  M.  D^  D.  D.  S. 


COPYHIO-HT.   1902 

BY    — 

Arthur  E.  Pbck 


Preee 

and 

Bindery 

A.  B.  Farnham  &  Co. 

Minneapolis 


t^a^ 


PREFACE 

T  N  presenting  this  system  of 
■*■  Porcelain  Inlay  to  the  dental 
profession,  I  do  so,  realizing 
that  it  is  but  a  step  forward 
in  the  progress  of  dental  art, 
and  as  such,  it  is  based  upon  the 
experience  and  discoveries  of  others, 
which  makes  it  difficult,  if  not  im- 
possible, to  trace  the  origin  of  an 
idea.  I  shall  not  attempt  to  give 
credit  to  whom  it  may  rightfully 
belong,  but  feel  grateful  to  those 
who  have  cleared  the  way;  and  in 
the  evolution  of  dentistry,  trust  that 
my  thought,  with  that  of  others, 
may  have  produced  a  system,  whose 
detail  of  the  technique  is  sufficiently 


clear  to  enable  the  many  to  obtain 
artistic  results  by  purely  mechanical 
steps.  Those  who  produce  accurate 
work  by  the  burnished  system,  do 
so  because  of  having  exceptional 
manipulative  ability,  which  is  as 
impossible  for  them  to  transmit  to 
others,  as  it  is  for  the  artist  to 
explain  how  he  produces  apparent 
life  in  his  pictures.  The  draughts- 
man obtains  artistic  results  by  the 
joining  of  lines  drawn  at  certain 
angles.  This  knowledge  is  trans- 
missable,  as  it  is  the  application  of 
a  principle,  by  mechanical  means, 
which  will  always  produce  a  certain 
result. 

The  author  of  this  work  has  en- 
deavored   to    formulate    a   system 


controlled  almost  entirely  by  me- 
chanical principles,  therefore,  it  can 
be  easily  followed  and  will  insure 
to  the  large  majority  as  uniform 
results  in  porcelain  as  those  ob- 
tained with  other  filling  materials. 


a — Matrix  Strip. 

Used  ior  taking  impression  of  the  cavity. 

b — Re-enforcing  Ring. 

Used  to  retain  the  backing  material  for  the 
impression. 

c — Die-Cup  Receptacle. 

For  holding  the  die-cup  and  plunger  while 
swaging. 

d — Die-Cup. 

For  holding  the  impression  die. 

e — Plunger. 

The  means  of  s-waging  the  matrix. 

f — Porcelain  Crusher, 
g — Baking  Strip. 

A  piece  of  fire-clay  on  which  the  inlay  is 
baked. 

h — Bottle  of  Liquid  Glaze, 
i — Asbestos  Cooling  Disk. 

On  which  the  inlay  is  placed  'when  baked. 

j — Cap  for  Cooling. 

Which  is  placed  over  the  inlay  while  cooling. 

k — Bottle  of  Inlay  Polish. 


PLATE    I. 


CHAPTER  INDEX 


Page 

A  System  of  Porcelain  Inky    . 

JO 

Cavities 

J5 

Color  and  Material 

48 

Taking  Impressions 

52 

Matrix  Formation 

56 

Method  for  Building  Anterior,  Con- 

tour and  Occlusal  Fillings, 

6S 

Fusing  the  Inlay 

74 

Contour,  Margins,  and  Insertion  o± 

the  Inlay         .... 

80 

Furnaces 

88 

The  Shadow  Problem 

90 

A  "W^ord  in  Conclusion 

94 

A  SYSTEM  OF  PORCELAIN 
INLAY 


P 


ORCELAIN  has  a  distinctive 
field  in  the  practice  of  dent- 
istry. It  is  not  calculated  to 
entirely  supplant  gold,  amal- 
gam, or  other  filliiig  materi- 
als, and  its  application  requires  good 
judgment  and  a  thorough  compre- 
hension of  its  limitations  as  well  as 
its  advantages. 

The  road  to  success,  in  this  class 
of  work,  is  not  an  easy  one,  but  the 
satisfaction  in  being  able  to  use 
porcelain  successfully  is  worthy  of 
the  effort. 

A  practical  case  should  not  be 
attempted  until  the  technique  has 

10 


been  thoroughly  mastered,  and  a 
cavity  of  each  class  has  been  pre- 
pared out  of  the  mouth.  A  com- 
plete knowledge  of  the  technique 
alone  will  insure  a  successful  oper- 
ation in  the  mouth.  This  fact  can- 
not be  impressed  too  emphatically. 

Porcelain  inlay  work  will  not 
admit  of  slighting  in  any  particular, 
therefore  any  short-cut  method 
should  be  thoroughly  investigated 
before  being  adopted,  as  it  usually 
leads  to  imperfections.  In  no  branch 
of  dentistry  is  painstaking  thorough- 
ness more  essential. 

For  this  system,  cavity  prepara- 
tion is  divided  into  eight  classes: 

I. — Cavities  iavolving  one  surface^  labial  cavities. 
2.— Cavities  involving  more  than  one  nuface, 
mesio-Iabial. 

n 


3t — Cavities  iavoWiaQ  mesio-labial-lingtial. 

4, —Cavities  in volviDg  mesio  -  labial  -  lingual  - 
iacisal. 

5. — Cavities  involving  labial-Iingual-indsal. 

6. — Cavities  involving  the  whole  incisal  edge. 

7. — Cavities  involving  the  approximal  and 
occlusal  surfaces  of  the  posterior  teeth. 

8. — Cavities  involving  the  whole  occlusal  sur- 
face of  the  posterior  teeth* 

The  three  initial  steps  in  cavity 
preparation  are  the  same  in  this  as 
in  all  others;  firsts  breaking  down  of 
undermined  enamel;  second^  re- 
moval of  the  softened  dentine;  third 
extension  for  prevention.  But  the 
fourth,  extension  for  retention,  is  a 
distinctive  feature  of  this  system, 
the  theory  of  ^ivhich  must  be  fully 
comprehended  before  any  attempt  to 
put  it  into  practice  in  the  mouth* 


J2 


PLATE   II. 


LABIAL  CAVITffiS 


T 


i^t^ 


HE  preparation  for  the  first 
class  (labial  cavities),  which 
involves  only  one  surface  of 
the  tooth,  differs  only  from 
the  usual  preparation  in  that 
the  walls  of  the  cavity  must  be  per- 
pendicular  to  the  respective  surfaces 
of  the  tooth  which  the  lines  of  the 
wall  intersect.  This  preparation 
gives  a  body  of  porcelain  whose 
lines  are  perpendicular  to  each  other, 
thus  giving  to  the  inlay  all  possible 
strength,  obviating  the  acute  angle 
(or  thin  fragile  edge),  which  is  to 
be  avoided  at  all  hazards. 

Plate  n.  Figure  A,  shows  a  full 
view  of  this  preparation. 

J5 


Figure  B  shows  a  cross-section 
from  the  incisal  edge  to  the  gingival 
border,  iflustrating  the  angle  of  the 
wafls  of  the  cavity  in  relation  to  the 
surface  of  the  tooth* 


M 


PLATE   III. 


MESIO-LABIAL 


T  NLAYS  for  cavities  of  the 
second  class,  which  involve 
the  labial  and  approximal 
surfaces  (but  not  the  lingual) 
are  inserted  without  a  separ- 
ation of  the  teeth.  Plate  HI,  Figures 
D  and  E,  show  the  method  of  prep- 
aration with  the  retention,  which  is 
obtained  by  means  of  a  groove  in 
the  bottom  of  the  cavity,  extending 
lengthwise  of  the  tooth.  It  will  be 
noticed  that  the  incisal  and  gingival 
borders  of  the  cavity  are  at  right 
angles  to  the  approximal  surface. 
This  gives  a  solid  body  of  porce- 
lain, which  is  very  essential  to  the 

19 


life  of  the  inlay.     Figure  F  shows 
the  inlay  with  the  retention  ridge. 

The    cross    section,    Figure    E, 
shows  the  groove  for  retention. 


PLATE    IV. 


MESIO-LABIAL-LINGUAL 


Q  AVITIES  of  the  third  class 
(mesio  -  labial  -  lingual) ,  give 
the  best  opportunity  for  artis- 
tic results.  In  this  class  we 
not  only  extend  for  preven- 
tion^  but  for  retention  also.  These 
fillings  should  be  inserted  from  the 
lingual  surface^  and  the  extension 
for  retention  must  extend  to  the 
firm  tooth  substance.  A  slight  groov- 
ing in  the  floor  of  the  cavity  near  the 
margin  on  the  lingual  surface,  as 
shown  by  Plate  IV,  Figures  G  and 
H,  will  give  a  perfect  retention  from 
all  lateral  pressure.  Figure  I  shows 
the  ridge  on  the  inlay. 

23 


The  wafls  of  the  cavity,  from  the 
lingual  surface  to  the  labial,  must 
be  slightly  v-shaped,  which  will 
avoid  loosening  from  lingual  pres- 
sure. Labial  strain  will  not  be 
sufficient  to  disturb  it. 

Cavities  of  this  class  can  approach 
the  incisal  edge  much  closer  than 
would  be  safe  in  preparing  for  a  gold 
filling.  It  is  the  force  of  the  blow  in 
the  operation  that  weakens  the 
enamel  prisms,  thus  causing  a  gold 
filling  to  fail.  But,  if  the  enamel 
rods  are  left  in  perfect  condition  and 
an  inlay  that  exactly  fits  is  cemented 
in,  they  then  have  nearly,  if  not 
the  same  support  they  had  before 
the  ravages  of  decay  set  in. 


2i 


PLATE    V. 


MESIO-LABIAL-LINGUAL- 
INCISAL 


n  AVITIES  of  the  fourth  class 
(  mcsio  -labial-Iingual-incisal ) 
are  the  most  difficulty  and  re- 
quire a  great  deal  of  good 
judgment,  skill  and  patience. 
Plate  V,  Figure  J,  represents  a 
typical  preparation  to  illustrate  this 
class  of  cavities.  The  formation  is 
such  that  most  of  the  retention  is  ob- 
tained by  means  of  grooves,  thus 
avoiding  a  deep  seat  in  the  tooth 
which  not  only  encroaches  on  the 
pulp  so  as  to  menace  the  life  of  the 
tooth  but  also  weakens  the  walls  and 
necessitates   a   wide    separation  to 

27 


admit  removal  of  the  impression  and 
insertion  of  the  filling. 

The  preparation  for  this  class  of 
cavities^  as  illustrated  by  Plate  V, 
is  as  follows: 

After  the  margins  for  the  labial 
and  approximal  surfaces  are  secured^ 
the  extension  for  retention  on  the 
lingual  surface  is  started  from  the 
incisa!  edge^  gradually  slooping  back 
to  the  firm  tooth  substance  near  the 
gingivo-Iingual  border,  keeping  well 
in  mind  that  the  walls  must  be  per- 
pendicular to  the  surface  of  the 
tooth.  For  this  preparation,  use 
first  the  Gem  Cavity  point  No.  J  3, 
S.  S.  W.,  followed  by  the  Fissure 
Bur  No.  57;  then  the  Fissure  Fin- 
ishing Bur  and  for  the  final  margin 

28 


when  accessible^  use  the  Arkansas 
Stone  point  No.  5,  S.  S.  W.  The 
Pear  shaped  Bur  is  used  for  the  re- 
tention groove.  Disks  can  be  used 
to  outline  the  cavities  but  the  final 
adjustment  of  the  margins  should 
always  be  made  with  the  Arkansas 
point  or  the  Fissure  Finishing  Bur. 

Retention  from  lateral  and  lingual 
strain  is  obtained  by  the  groove  in 
the  base  of  the  cavity  as  illustrated 
by  Figure  K,  which  is  a  cross-sec- 
tion of  Figure  J. 

A  cavity  prepared  on  this  princi- 
ple wjII  not  require  a  separation  to 
remove  the  impression,  or  to  insert 
the  filling. 

It  will  be  readily  understood  that 
the  principle  of  retention  is  grool?es 

29 


instead  of  a  deep  seat  in  the  cavity. 
A  groove  should  be  made  wherever 
it  wiH  resist  the  strain  of  mastica- 
tion. 

The  grooves  must  be  made  so 
that  the  impression  %>r7/  draJi)* 
The  cuts  are  intended  to  illustrate 
only  the  typical  cases  and  make 
clear  the  principles  involved.  The 
advantages  in  this  system  of  cavity 
preparation  are:  that  a  groove  or 
depression  at  points  in  the  cavity 
will  not  endanger  the  pulp,  and 
give  a  much  better  retention  for  the 
filling  than  the  ordinary  saucer- 
shaped  cavity.  It  also  avoids  the 
necessity  for  a  wider  separation  than 
for  gold. 


30 


PLATE    VI. 


LABIO-LINGUAL-INCISAL 


C  AVITIES  of  the  fifth  class, 
involving  labio-Iingual-incis- 
alf  arc  illustrated  on  Plate 
VI,  Figure  M.  While  the 
cavity,  at  first  glance,  seems 
to  show  a  v-shape,  it  will  be  noticed 
that  for  a  short  distance  back  from 
the  incisal  edge  the  walls  are  per- 
pendicular to  the  incisal  surface. 
This  is  essential,  as  it  gives  a  solid 
piece  of  porcelain  without  the  fragile 
edge.  A  slight  groove  down  the 
sides  and  across  the  base  of  the  cav- 
ity will  give  it  sufficient  retention 
and  yet  allow  an  impression  to  be 
drawn  from  it.   Figure  N  is  a  cross- 

33 


section  gingivo-incisal,  showing  re- 
tention groove.  Figure  O  shows 
the  inlay  with  its  retention  ridge. 


0 


PLATE    VII. 


INCISAL  EDGE 


U 


^*fc?* 


NDER  the  sixth  class  we 
have  a  cavity  involving  the 
whole  incisal  edge.  Plate 
VHf  Figures  P  and  Q,  illus- 
trate the  preparation,  which 
is  made  mostly  by  means  of  a  stone, 
slightly  grooving  the  center  of  the 
cavity,  mesio-distally,  and  bringing 
the  margins  at  the  labial  and  lingual 
surfaces  to  a  sharp  edge.  On  eith- 
er side  of  the  pulp  a  slight  depres- 
sion is  made  with  a  round  bur  to 
mark  the  place  for  the  pins  to  be  in- 
serted. This  will  be  transferred  to 
the  matrix,  giving  a  correct  guide 
for   placing    the   pins.      Figure  R 

37 


shows  the  inlay  with  the  pins  in 
position.  The  pins  should  be  about 
21  standard  gauge. 


/^ 


PLATE   VIII. 


APPROXIMAL   AND 
OCCLUSAL 


P  AVITIES  of  the  seventh 
class,  involving  the  approx- 
imal  and  occlusal  surfaces  of 
the  posterior  teeth,  must  be 
cut  well  out  to  bucal  and  lin- 
gual surfaces;  unless  this  is  done  it  is 
almost  impossible,  especially  with 
the  occlusal  surface,  to  get  perpen- 
dicular walls  of  porcelain,  so  essen- 
tial to  strength.  Plate  VIII,  Figure 
S,  is  a  view  looking  down  into 
the  cavity.  Figure  T,  same  plate, 
is  a  cross-section  showing  the  loca- 
tion of  pins.  Figure  U  shows  the 
inlay  with  one  of  the  retention  pins. 

41 


Figure  V  shows  the  inlay  with  a 
correct  angle  of  porcelain  on  the 
right  and  an  imperfect  shape  (acute 
angle)  on  the  left^  that  is  almost 
certain  to  be  made  unless  the  cavity 
is  cut  well  out  to  the  margins. 

To  be  successful  in  this  class  of 
cavities,  where  so  great  a  pressure 
is  brought  to  bear,  a  solid  body  of 
porcelain  is  absolutely  necessary. 
Pins  are  preferable  to  grooves  for 
retention.  With  a  round  bur  make 
a  slight  depression  at  the  point  in  the 
cavity  where  the  pins  are  to  be 
placed.  This  will  be  tranferred  to 
the  impression  and  in  turn  to  the 
matrix.  After  the  matrix  is  invest- 
ed in  the  investing  material  (which 
hardens  in  a  short  time)  the  matrix 

42 


can  be  perforated  at  the  point  indi- 
cated by  the  depression  and  the 
pin  inserted  into  the  investment^ 
allowing  the  point  to  project  a  suffi- 
cient distance  to  support  the  inlay. 
The  investment  material  will  hold 
the  pin  in  position  while  fusing. 


0 


48 


POSTERIOR  OCCLUSAL 


«^«5* 


r*  AVITIES  of  the  eighth  class, 
involving  the  occlusal  sur- 
faces of  the  posterior  teeth, 
open  a  field  worthy  all  the 
time  and  expense  required  to 
become  proficient  in  this  class  of 
work.  To  be  able  to  restore  with 
porcelain  the  contour,  color  and 
service  of  teeth  that  have  been  worn 
off  so  much  as  to  require  the  bite  to 
be  opened  is  certainly  a  great  step  in 
dentistry,  and  the  restoration  in  cases 
of  this  class  with  unsightly  gold 
fillings  may  now  be  a  practice  of  the 
past, 

Plate  DC,  Figure  W,  gives  a  view 
of  this  preparation,    showing    the 

44 


PLATE    IX. 


grooves  and  depressions  marking 
the  site  of  the  pins.  Figure  X 
gives  a  view  of  the  inlay  with  its  re- 
tention ridges  and  pins  in  position. 
(See  special  instruction  for  mat- 
rix formation  and  placing  the  pins 
in  the  chapter  on  Matrix  Forma- 
tion.) 


a 


47 


A 

COLOR  AND  MATERIAL 

NY  of  the  porcelain  bodies  on 
the  market,  either  high — or 
low — fusing,  may  be  used 
with  this  system.  The  fol- 
lowing method  for  obtaining 
color  is  given  because  it  is  the  one 
used  exclusively  by  the  writer  in 
his  practice,  and  in  giving  it  he  does 
so,  believing  it  to  be  one  of  the  most 
simple  and  satisfactory  known  to 
the  profession.  Select  a  tooth  a  shade 
lighter  than  the  color  of  the  tooth  to 
be  matched.  With  a  pair  of  excising 
forceps  remove  that  portion  of  the 
tooth  desired,  and  grind  out  of  it  any 
color  not  wanted.  Then  it  is  pul- 
verized in  the  crusher  (f,  Plate  I)^ 


and  removed  to  a  Wedgewood  mor- 
tar, which  should  be  kept  for  this 
purpose  alone,  and  therein  ground 
to  an  impalpable  powder,  which 
fuses  at  a  lower  temperature  than 
the  original  porcelain  tooth,  owing 
to  its  being  pulverized  to  a  much 
finer  degree  than  it  was  in  the 
original  baking. 

Often  times  it  is  advisable,  par- 
ticularly in  large  contour  fillings,  to 
shade  the  inlay.  If  so,  usually  the 
neck  of  the  tooth  will  answer.  This 
is  treated  the  same  as  the  tip  and 
blended  with  the  other  color  when 
building  the  inlay. 

While  this  method  of  getting  color 
is  positive,  as  stated,  it  must  be  re- 
membered that  the  light  at  the  time 

49 


the  tooth  is  selected  may  not  be  the 
same  as  when  it  is  put  in.  Here  is 
an  occasion  when  experience  and 
judgment  alone  will  insure  positive 
results.  The  rule  is  to  select  the 
porcelain  tooth  just  a  shade  lighter 
than  the  tooth  to  be  matched,  so  as 
to  allow  for  shadow  effect  of  the 
cement.  This  method  of  obtaining 
color  must  be  used  because  of  the 
cement  which  we  now  have,  but  if 
a  transparent  cement  can  be  ob- 
tained, then  the  color  of  the  tooth 
must  be  matched  exactly,  as  there 
will  be  no  shadow  reflection  to 
overcome. 

Cleanliness  is  an  important  matter 
in  making  an  inlay  and  the  slightest 
particle  of  dust  or  powder  from  the 

50 


previous  bake,  if  left  in  the  mortar, 
will  change  the  color. 

The  steel  mortar  and  pestle  should 
be  thoroughly  cleaned  with  gasoline 
when  it  is  received,  and  wiped  with 
a  clean  cloth  each  time  before  using. 
Slight  particles  of  iron  or  grease 
may  be  found  in  the  mortar  for 
some  time.  It  is  of  vital  impor- 
tance to  remove  every  particle  of 
iron  yt>ith  a  magnet  immediately 
after  it  comes  from  the  steel  mortar. 


5} 


TAKING  IMPRESSIONS 


t^«3* 


T  T  is  not  necessary  to  put  the 
rubber  dam  on  to  take  an 
impression.  Place  a  folded 
strip  of  cottonoid  under  the 
lip;  dry  the  cavity  and  dust 
well  with  soapstone;  then  allow  the 
patient  to  bite  on  another  piece  of 
cottonoid;  mix  the  cement  (which 
should  be  Britton^s  yellow  powder) 
to  a  consistency  which  will  allow  it 
to  be  handled  with  the  fingers.  Into 
the  cement  incorporate  a  sufficient 
amount  of  soapstone  until  the  ad- 
hesiveness is  destroyed.  Plate  X, 
Figure  Y^  represents  the  cavity  of 
which  the  impression  is  to  be  taken. 
The  matrix  strip  being  placed  be- 
52 


twccn  the  teeth,  the  cement  is  then 
crowded  into  the  cavity  from  the  side 
of  the  tooth  into  which  the  filling  is 
to  be  inserted  (Plate  X,  Figure  Z) 
and,  as  soon  as  it  is  in  place,  the 
matrix  strip  is  bent  onto  the  cement 
from  both  sides,  holding  it  in  posi- 
tion until  it  is  nearly  hard.  Remove 
the  matrix  strip  and  chisel  off  care- 
fully the  surplus  cement.  Draw  a 
sandpaper  strip  through  to  be  sure  it 
is  clear  from  the  adjoining  tooth; 
then  remove  the  impression. 

To  get  an  impression  of  the 
occlusal  surface,  encircle  the  tooth 
in  question  with  a  piece  of  the  mat- 
rix strip  (a,  Plate  I),  having  it  wide 
enough  to  extend  above  the  end  a 
trifle;  hold  the  ends  of  the  strip  to- 
53 


g^ether  and  crowd  the  cement  down 
on  top  of  the  tooth.  When  hard, 
remove  the  strip  and  take  out  the 
impression* 

To  take  the  impression  for  labial 
cavities  extending  under  the  gums, 
dust  the  cavity  with  soapstone.  Pre- 
pare the  cement  as  for  other  impres- 
sions, having  first  cut  a  strip  of 
metal,  similar  in  shape  to  a  gum 
retractor;  with  this  crowd  the  gum 
back  and  press  the  cement  to  place 
with  the  fingers,  holding  the  cement 
and  the  retractor  in  position  until  it 
is  hard. 

Cement  mixed  to  this  consistency 
has  a  tendency  to  crowd  out  at  the 
points  of  least  resistance  and  would^ 
unless  the  pressure  were  evenly  dis- 

54 


trihutcdf  give  an  incorrect  impres- 
sion of  the  cavity.  The  pressure  of 
the  matrix  strip  being  equal,  a  perfect 
impression  is  obtainable,  which  is 
the  foundation  to  build  on  and  must 
be  exact. 


J^ 


M 


MATRIX  FORMATION 

ATRIX  formation  is  the  next 
step  in  the  process  of  porce- 
lain inlay.  While  it  is  of  the 
highest  importance,  it  is  diffi- 
cult to  lay  stress  on  any  one 
point  as  being  more  essential  than 
another.  Each  link  in  the  chain  of 
this  work  must  be  perfect,  differing 
from  other  operations  in  the  fact 
that  a  failure  in  any  part  of  the  oper- 
ation is  fatal. 

It  is  impossible,  in  a  majority  of 
cavities  prepared  by  this  system,  to 
obtain  perfect  adaptation  to  all  parts 
of  the  cavity,  except  by  swaging,  it 
being  essential  that  the  whole  sur- 
face  be  perfectly   covered,   as   the 

56 


PLATE   X. 


retention  of  the  inlay   depends  on 
this  feature. 

By  the  system  which  this  treatise 
exemplifies,  contraction  and  expan- 
sion are  perfectly  controlled,  thereby 
allowing  an  inlay  to  be  made  which 
exactly  fits  all  parts  of  the  cavity. 
To  obtain  this  result,  a  correct  im- 
pression of  the  cavity  must  be  taken. 
The  convex  surface  of  the  impres- 
sion represents  the  exact  inside  of 
the  cavity;  the  concave  surface  of 
the  matrix  swaged  to  fit  this  also 
represents  the  exact  inside  of  the 
cavity.  A  filling  baked  to  this  con- 
cave surface  after  removing  the 
matrix,  must  be  a  duplicate  of  the 
impression,  and  if  contraction  and 
expansion  are  controlled,  must  fit  the 
cavity  perfectly.   59 


If  the  instructions  in  cavity  pre- 
parations are  followed  closely  one 
will  have  no  undercuts;  and  with 
a  good  impression  the  making  of 
a  correct  matrix  is  positive. 

The  impression  (Plate  X,  Figure 
AA),  taken  by  the  process  pre- 
viously explained^  is  backed  with 
cement  in  the  re-enforcing  ring 
(Plate  X,  Figure  AB),  as  the 
strength  of  the  impression  unsup- 
ported would  not  be  sufficient  to 
withstand  the  strain  to  which  it  is 
necessary  to  subject  it. 

Use  Britton's  yeflow  for  the  im- 
pression,  and  the  grey  for  the  re- 
enforcing.  The  color  will  enable 
them  to  be  distinguished  and  so  pre- 


vent  the  re -enforcement  from  en- 
croaching upon  the  impression. 

When  hard,  remove  with  a  bur 
or  chisel  the  portion  of  the  impres- 
sion and  re -enforcement  that  would 
interfere  with  the  swaging  of  a 
matrix  or  the  drawing  of  a  counter- 
die;  this  latter  feature  is  very  im- 
portant as  a  perfect  matrix  may  be 
spread  sufficiently  to  spoil  it  in  the 
removal  from  the  impression* 

Invest  the  re-enforced  impression 
in  the  die-cup,  using  modeling  com- 
pound for  the  investing  material; 
trim  off  the  surplus  and  take  a  piece 
of  platinum  J -1000  inch  in  thick- 
ness, large  enough  to  cover  the 
impression,  and  form  this  to  the  im- 
pression, using  Flaggs'  instrument 

6} 


No.  33^  made  by  S.  S.  W.  Fold  the 
platinum  on  itself  whenever  it  is 
necessary.  The  folding  prevents 
tearing,  and  can  be  burnished  out 
when  it  is  worked  down  on  the  die. 
It  is  then  annealed  and  returned  to 
the  die-ring.  Place  the  die-cup 
(Plate  X,  Figure  AC)  in  the  die- 
cup  receptacle  (c,  Plate  I). 

Now  place  a  small  ball  of  mouldine 
on  the  matrix  and  with  the  plunger^ 
drive  it  home  hard.  Mouldine  gives 
the  best  results,,  but  other  materials 
may  be  used,  including  rubber,  soap, 
cement,  etc.  Remove  the  plunger, 
wipe  off  the  mouldine,  and  with  the 
small  end,  force  the  die -cup  out  of 
the  receptacle,  then  burnish  the 
margins  of  the  inlay  with   a   bur- 

62 


nisher  No.  34,  S.  S.  W.  This  will 
give  a  perfectly  sharp  margin.  Now 
remove  the  matrix  and  make  incis- 
ions about  one -eighth  of  an  inch 
apart  extending  around  the  border 
of  the  matrix;  anneal  and  strike  with 
the  swage  again.  Now,  with  a  chisel 
placed  on  the  matrix  just  back  of 
the  margin,  turn  up  the  matrix  in  as 
many  places  as  possible,  using  a 
sharp  knife  to  place  under  the  edges 
of  the  platinum  in  turning  it  back  on 
to  the  chisel,  producing  the  results 
as  shown  in  Plate  X,  Figure  AD. 
These  edges  and  comers  will  engage 
the  investment,  which  is  poured  on 
the  matrix  at  this  stage,  having  first 
oiled  the  parts  surrounding  the 
matrix  to  prevent  the  investment 


sticking.  This  investment,  incor- 
porating the  edges  of  the  matrix, 
will  prevent  contraction  and  expan- 
sion, thus  insuring  a  perfect  fitting 
inlay,  providing  the  previous  in- 
structions are  closely  followed.  The 
matrix  being  re-enforced  on  the  die 
with  the  investment  material,  pre- 
cludes any  possibility  of  changing 
its  form  while  removing  Figure 
AE  shows  the  invested  matrix  in 
the  die-cup.  Figure  AF  shows  the 
invested  matrix  ready  to  receive  the 
porcelain  for  baking. 

Figure  AG,  Plate  X,  iflustrates 
the  invested  matrix  of  the  eighth 
class  of  cavities,  showing  the  pins 
in  position  to  be  fused  in  the  inlay. 
The  perforation  through  the  matrix 

64 


must  not  he  made  with  a  bur.  An 
instrument  a  litttle  larger  than  the 
pin  should  be  sharpened  to  a  three 
sided  spear  point  and  carefully 
worked  through  the  matrix  into  the 
investment^  and  the  pins  inserted 
therein. 

The  investment  material  must  be 
of  such  a  nature  that  the  extreme 
heat  will  not  change  its  form;  if  it 
expands  or  contracts  at  all,  it  will 
draw  the  matrix  with  it.  This  in- 
vestment becomes  sufficiently  hard 
to  admit  of  perforation  without 
danger  of  changing  its  form,  allow- 
ing pins  to  be  placed  through  the 
matrix  into  the  investment  which 
holds  them  in  position  while  they 
are  fused  in  the  inlay. 

65 


A  METHOD  FOR  BUILDING 
ANTERIOR  CONTOUR  AND 
OCCLUSAL  FILLINGS. 


t^i^ 


17  OR  an  explanation  of  this 
method^  a  cavity  of  the  fourth 
class  (Plate  XI^  Figure  AH), 
advanced  through  the  various 
stages  to  completion,  will 
serve  to  illustrate  the  principles 
involved,  which  can  also  be  applied 
to  occlusal  cavities. 

After  the  cement  impression  has 
been  taken,  as  previously  described, 
crowd  a  piece  of  soft  modeling  com- 
pound into  the  cavity  and,  while  in 
position,  trim  until  it  represents  an 
inlay  of  the  desired  shape.  Plate 
XI,  Figure  AI,  shows  the  compound 

66 


PLATE   XI. 


inlay  in  position.  Remove  this  in- 
lay and  place  it  on  the  invested 
matrix  (Figure  AJ),  which  repre- 
sents the  cavity  from  which  it  has 
been  taken.  If  it  fits  the  platinum 
matrix,  you  can  feel  sure  of  a  perfect 
fitting  inlay,  as  this  step  will  prove 
the  correctness  of  your  work.  Now 
fasten  the  modeling  compound  inlay 
to  the  matrix  on  the  lingual  side 
with  wax.  Dust  the  investment 
and  compound  inlay  with  soapstone 
and  mix  a  sufficient  quantity  of 
cement  according  to  the  instructions 
previously  given  for  taking  an  im- 
pression. Crowd  this  over  the 
modeling  compound  inlay,  but  do 
not  allow  the  cement  to  extend 
beyond  the  platinum  as  it  will  adhere 

69 


to  the  plaster  and  be  apt  to  disturb 
the  matrix  when  it  is  removed. 

The  cement  counter-die  is  now 
removed  and  invested  in  the  die-cup, 
and  a  platinum  counter-matrix  struck 
up.  To  do  this  without  tearing  the 
matrix,  dust  the  cement  counter-die 
with  soapstone,  then  warm  the  end  of 
a  piece  of  modeling  compound  over  a 
flame  and  after  moistening  fingers  in 
water,  draw  it  down  to  a  point  and 
press  it  in  to  the  cement  counter-die. 

This  modeling  compound  die  will 
serve  to  form  the  platinum  over,  as 
it  can  be  folded  on  itself  so  as  to 
prevent  tearing;  and  while  the  plat- 
inum is  on  the  modeling  compound 
die,  force  it  into  the  cement  counter- 
die.     Now    remove  the  modeling 

70 


compound,  leaving  the  platinum 
matrix  in  the  cement  counter-die 
and  place  the  die-cup  in  the  die-cup 
receptacle  and  swage  it  to  place, 
following  instructions  found  in  the 
chapter  on  matrix  formation.  The 
counter-matrix  is  then  removed 
and  invested  in  the  investing  ma- 
terial which  can  be  held  over  the 
flame  to  hasten  the  setting.  Both 
the  platinum  counter-die  and  mat- 
rix are  covered  with  a  thin  layer  of 
porcelain,  the  color  desired  for  the 
surface  of  the  finished  inlay  and 
baked  to  a  bright  glaze.  The 
foundation  colors  are  laid  last,  the 
reverse  of  the  usual  methods.  The 
porcelain  must  not  encroach  on  the 
margins   as  it   would  prevent  the 

71 


approximation  of  the  platinum 
counter-matrix  with  the  matrix. 
The  porcelain  is  then  fused  in  the 
counter-matrix  until  it  is  nearly  full; 
this  usually  requires  two  or  three 
bakings.  If  you  should  get  a  sur- 
plus of  porcelain  in  the  counter- 
matrix,  with  a  gem  stone,  grind  out 
enough  to  aflow  the  parts  to  go  to 
place,  then  apply  a  quantity  of  moist 
porcelain  powder  on  the  approximat- 
ing surfaces  and  gently  crowd  them 
together.  If  this  is  found  to  be 
difficult,  moisten  the  powder  freely 
and  it  will  go  to  its  proper  position. 
The  counter-matrix  and  matrix  are 
now  fused  together. 

When  this  is  done,  remove  the 
platinum  counter-matrix  and  with  a 

72 


INSERT. 

A  METHOD  FOR  MAKING  A  YAA- 
TRIX  AND  COUNTER  MATRIX 
IN  ONE  PIECE  FOR  CAVITIES 
OF  THE  FOURTH  AND  SIXTH 
CLASSES. 


<^»p* 


"^^T ITH  a  disk,  shape  the  cement 
impression  on  the  labial,  ap- 
proximal  and  incisal  surface, 
in  duplicate  of  the  desired  in- 
lay, making  them  perfectly- 
smooth.  This  contouring  must  be 
done  before  the  removal  of  the  im- 
pression from  the  tooth.  If  there  is 
not  enough  cement  to  give  perfect 
approximal  contact,  remove  the  im- 
pression and  add  to  it  the  requisite 


amount,  trying  it  into  the  tooth,  to 
prove  this  point;  now  reinforce  and 
invest  the  impression.  The  concave 
surface  of  a  matrix  struck  up  on  the 
impression  of  the  cavity  and  extend- 
ing over  the  surface  of  the  cement 
which  was  contoured,  will  give,  in 
one  piece,  a  matrix  for  the  cavity 
and  a  mold  in  which  to  bake,  giving 
all  the  contour  of  the  filling  with 
the  exception  of  the  lingual  surface 
which  can  be  brought  to  its  proper 
form  with  a  brush. 


brush,  fill  in  any  defects  in  the  sur- 
face and  fuse  to  a  velvet  gloss.  This 
will  produce  an  inlay  slightly  larger 
in  all  directions,  but  in  the  true  al- 
lignmcnt,  it  is  finished  according  to 
instructions  found  on  Contour,  Mar- 
gins and  Insertion  of  the  Inlay,  the 
above  method  for  building  a  contour 
filling  should  be  used  in  cavities  of 
the  fourth,  sixth,  seventh  and  eighth 
classes. 


73 


FUSING  THE  INLAY 


T 


i^e^ 


HE  fusing  temperature  of  the 
teeth  manufactured  by  S,  S. 
White  &  Co.,  Justi  &  Son, 
and  the  Consolidated  Dental 
Manufacturing  Co.,  is  taken 
as  a  basis  for  the  temperature  in  the 
following  explanation. 

The  basis  for  the  time  for  fusing 
is  regulated  by  the  melting  of  a 
pellet  of  gold  in  the  furnace.  On 
account  of  the  divergent  opinions  of 
authorities,  the  degree  of  tempera- 
ture for  fusing  the  porcelain  is  not 
stated  and,  as  experience  has  shown, 
the  comparison  with  the  melting  of 
a  pellet  of  gold  is  sufficiently  accu- 
rate. 

74 


For  the  first  bakingt  place  a  thin 
even  layer  of  powder  over  the 
matrix,  just  enough  to  cover  it,  then 
with  your  brush,  clean  a  strip  about 
1-32  of  an  inch  in  width  around  the 
part  of  the  matrix  representing  the 
margin  of  the  cavity  and  fuse  to  a 
bright  glaze.  This  margin  must  be 
kept  clean  from  porcelain  for  the  first 
two  bakings.  The  building  of  the 
inlay  for  the  second  baking  depends 
upon  the  class  of  cavities  involved. 
If  it  is  for  the  first,  second,  third  or 
fifth  class,  one  can  follow  the  lines 
of  the  matrix,  building  the  inlay  a 
little  more  than  full.  If  it  is  for  the 
fourth,  sixth,  seventh  or  eighth 
class  the  instructions  on  page  6^, 
for  building  contour  fillings  should 

75 


be  followed.  The  second  baking 
should  be  from  fifteen  to  twenty 
seconds  less  than  the  first,  and  the 
succeeding  bakings  fifteen  seconds 
less  than  the  second.  This  system 
aims  not  to  disturb  the  first  baking 
with  the  second,  or  the  second  with 
the  third.  The  last  coat  should  be 
brought  to  a  satin  gloss.  It  usually 
requires  three  bakings  to  complete 
the  inlay.  The  time  required  to 
obtain  the  bright  glaze  of  the  first 
baking  cannot  be  given,  as  it  de- 
pends on  the  stability  of  the  electric 
current,  the  button  which  the  control 
lever  rests  on,  the  winding  of  the 
muffle,  and  the  porcelain  used.  This 
may  require  some  experimenting, 
but  can  soon  be  obtained  by  placing 

76 


a  pcUet  of  gold  just  inside  the  furnace 
door  and  taking  your  time  from  the 
melting  of  the  gold  until  you  get  the 
bright  glaze*  Then  follow  the  pre- 
vious instructions  for  each  succeed- 
ing baking.  This  rule  also  holds 
good  with  the  gasoline  furnace. 
Great  care  should  be  taken  to  prevent 
all  drafts  from  striking  the  furnace 
while  baking.  After  each  bakings 
and  while  the  furnace  is  at  its  max- 
ium  temperature^  the  inlay  should  be 
removed  to  the  asbestos  cooling  disk, 
and  covered  immediately  with  the 
cooling  cap  (Plate  I),  which  should  be 
previously  heated  by  setting  on  top 
of  the  furnace  while  baking.  Allow 
it  to  remain  over  the  inlay  until  it 
is  at  the  temperature  of  the  room  be- 

77 


fore  opening,  as  disatrous  results  will 
follow  if  this  point  is  not  observed. 
It  should  be  remembered  that  the 
margins  of  the  inlay  must  be  well 
covered  at  the  last  bake,  as  the 
writer  is  a  firm  believer  in  the  ground 
margin  instead  of  a  fused  one.  My 
experience  with  the  fusing  of  porce- 
lain shows  either  a  rounded  margin, 
or  a  sharp,  overhanging  edge,  either 
one  being  undesirable.  The  over- 
hanging edge  resting  on  the  tooth 
beyond  the  margin  of  the  filling, 
prevents  the  true  adaptation  of  the 
inlay  from  being  seen.  This  con- 
dition presents  to  the  casual  observ- 
er a  pleasing  appearance,  but  the 
careful  operator  ought  not  to  be 
satisfied  with  a   condition  of   this 

78 


kind.  A  gold  filling  that  protruded 
beyond  the  tooth  would  not  be  toler- 
ated, and  we  should  not  allow  the 
same  condition  to  exist  with  porce- 
lain. This  frail  margain  is  sure  to 
chip  sooner  or  later,  leaving  an  un- 
sightly blemish. 


0 


79 


I 

CONTOUR,    MARGINS,   AND 
INSERTION  OF  THE  INLAY 

N  this  chapter  we  will  con- 
sider three  methods  for  ob- 
taining contour  and  margins. 
The  first  two  methods  arc 
applicable  to  cavities  of  the 
first,  second,  third  and  fifth  classes. 
With  this  method  the  inlay  is 
taken,  after  it  is  baked  and  still  in 
the  investment,  to  the  lathe  and 
ground  until  the  margins  of  the 
matrix,  which  represent  the  outline 
of  the  cavity,  are  visible;  then  the 
matrix  is  removed  and  the  inlay 
cemented  in  the  tooth.  If  it  was  not 
ground  to  a  perfect  contour  of  the 
tooth,  it  should  be  completed  in  the 

80 


mouth  by  the  methods  used  for  fin- 
ishing a  gold  filling^  using  the  Gem 
stones,  Arkansas  stones  and  fine 
sand  paper  and  cuttle  fish  disks  and 
strips.  Then  for  the  final  polish  use 
wooden  points  with  polishing 
powder.  The  results  of  this  method 
are  entirely  satisfactory  providing 
the  porcelain  is  not  porous. 

•5*   t^   J* 

The  procedure  for  the  second 
method  is  begun  by  obtaining  a 
counter-die  of  cement;  this  must  not 
be  taken  until  the  matrix  is  swaged. 
The  die  should  then  be  dusted  with 
soap  stone  and  placed  in  the  die-cup 
receptacle,  with  the  counterdie-ring 
in  position,  having  the  thumb  screw 
well  to  place.  Then  prepare  a  small 
mix  of  Britton^s  grey  powder,  the 


same  as  for  taking  the  impression^ 
and  drop  it  into  the  counterdie-ring. 
The  plunger  is  placed  in  position 
and  with  a  mallet  tapped  a  few 
times.  When  the  cement  is  hard, 
the  die-cup  and  counterdie-ring  are 
removed  by  means  of  an  instrument 
forced  through  the  hole  in  the 
bottom  of  the  die -cup  receptacle; 
now  tap  the  plunger  lightly  until 
the  die  is  disengaged.  If  care  is 
taken  this  will  give  you  a  counter- 
die  which  is  a  duplicate  of  the  cavity. 
After  removing  the  matrix  the  inlay 
is  stuck  in  the  cement  counterdie 
with  wax,  and  ground  to  the  desir- 
ed contour  on  the  lathe.  A  Hindo- 
stan  stone  is  par  exellence  for  this 
work,  as  it  gives  a  beautiful  margin 


and  leaves  the  fillings  in  a  majority 
of  casest  polished  perfectly.  But  if 
you  should  desire  to  enamel  the  in- 
lay^ remove  the  wax  with  alcohol, 
replace  it  in  the  cement  counterdie, 
or  invest  it  in  the  investment  material 
and,  with  a  clean  brush,  cover  the 
exposed  portion  of  the  inlay  with  a 
thin  coat  of  glaze,  place  it  in  the 
furnace  until  the  heat  clears  it  up  per- 
fectly. This  will  sometimes  give  too 
high  a  polish;  if  so  it  can  be  reduced 
with  a  cuttle  fish  disk.  The  same 
precautions  should  be  observed  in  re- 
moving it  from  the  furnace  as  when 
bakingc 

Quite  a  different  procedure  is  nec- 
essary to  obtain  the  correct  contour 
of  cavities  of  the  fourth,  sixth,  sev- 
enth and  eighth  classes,  and  for  an 

83 


explanation  of  this  method  we  will 
consider  cavities  of  the  fourth  class, 
mesio  -  labial  -  lingual  -  incisal,  taking 
the  inlay,  baked  according  to  the 
instructions  under  the  previous  chap- 
ter, for  contour  operations,  which 
gives  us  a  filling  slightly  larger 
in  all  directions  than  it  should  be 
to  harmonize  with  the  contour  of 
the  tooth.  We  now  remove  the 
matrix  and  grind  the  approximal 
surface  on  the  lathe,  using  a  fine 
corborundum  stone,  until  the  filling 
will  go  to  place.  It  is  then  retained 
in  position  by  means  of  a  wedge, 
and  with  modeling  compound  an 
impression  is  taken  of  the  tooth 
containing  the  inlay,  and  the  adjoin- 
ing one.    Before  removing  the  im- 

84 


prcssion^  take  out  the  wedge;  this 
will  allow  the  inlay  to  come  away 
with  the  modeling  compound,  fill 
this  impression  with  a  quick  setting 
cement;  the  part  of  the  cement  com- 
ing in  contact  with  the  inlay  should 
be  very  soft  so  as  to  obtain  the  re- 
quired retention.  After  you  have 
placed  a  little  of  this  thin  cement  on 
the  inlay,  work  a  little  more  powder 
in  the  remaining  cement  and  crowd 
it  to  place;  when  hard,  remove  the 
modeling  compound  and  you  have 
the  inlay  in  a  cement  tooth,  showing 
the  proper  alignment  with  the  rest 
of  the  teeth.  A  sharp  instrument 
placed  between  the  cement  tooth 
with  the  inlay,  and  the  adjoining  one 
will  separate  them.    The  inlay  will 

&5 


be  attached  sufficiently  hard  to  allow 
the  contour  to  be  ground  on  the 
lathe.  If  the  polish  is  sufficient  after 
using  the  Hindostan  stone,  it  can  be 
removed  from  the  investment  and 
cemented  to  place.  If  further  polish 
is  desired,  follow  the  previous  in- 
structions in  this  chapter. 

When  ready  to  set,  roughen  the 
cavity,  and  grind  the  inside  of  the 
inlay  with  a  3-16  inch  fissure 
diamond  disk,  so  as  to  engage  the 
cement.  The  inlay  should  be  kept 
wet  while  grinding  to  prevent  dark- 
ening. 

Harvard  white  cement  should  be 
used  in  setting  all  inlays.  By  mix- 
ing a  nearly  equal  amount  of  water 
with  the  fluid,  it  will  set  perfectly  in 

86 


ten  minutes.  Inlays  for  the. fourth 
class  are  held  in  position  while  set- 
ting by  inserting  a  wedge  between 
the  inlay  and  the  adjoining  tooth. 

It  is  not  necessary  for  cavities  in 
the  anterior  teeth,  to  use  the  rubber 
dam.  A  piece  of  cottonoid  placed 
under  the  lip,  and  another  piece  for 
the  patient  to  bite  on  will  give  you 
all  the  time  necessary  for  the  cement 
to  harden. 


0 


87 


FURNACES 


IT  HE  furnace  to  be  used  in 
Porcelain  Inlay  work  is  a 
matter  of  considerable  impor- 
tance^ but  a  discussion  of  this 
subject  cannot  be  made  a  por- 
tion of  a  treatise  of  this  character. 
The  author  uses  the  Hammond 
Electric  and  the  Turner  Gasoline 
furnaces.  There  may  be  others 
equally  serviceable. 

The  explanation  under  the  head- 
ing of  ^^Fusing"  in  the  treatise  is 
based  upon  experience  with  the  elec- 
tric furnace. 

In  using  the  gasoline  furnace  it  is 
advisable  to  give  it  at  least  twenty 
minutes  to  heat  up  before  starting  to 

8& 


fuse.  Then  the  inlay  is  placed  on 
the  hearth  until  dry,  and  gradully 
moved  into  the  back  of  the  furnace. 
The  fusing  strip  should  be  placed 
against  the  back  of  the  furnace,  and 
a  small  piece  of  fire  clay  placed 
against  the  front  end  of  this  strip. 

The  pellet  of  gold  should  be  placed 
on  the  fire  clay  next  to  the  fusing 
strip,  and  not  more  than  one-fourth 
inch  from  the  edge,  and  the  mica 
door  should  be  used  instead  of  the 
fire  clay  plug  to  admit  of  vision. 

Then  follow  the  instructions  on 
page  76. 


8f 


I 


THE  SHADOW  PROBLEM 

N  considering  the  shadow 
problem,  three  things  well 
taken  care  of  will  eliminate 
most  of  the  difficulties  in  that 
direction*  If  the  cavity  is  so 
prepared  that  the  wafls  are  perpen- 
dicular to  the  surface  of  the  tooth,  it 
wiD  give  a  body  of  porcelain  whose 
shadow  reflection  will  be  the  same 
at  the  margin  as  it  is  in  the  middle* 
This  point  cannot  be  emphasized  too 
strongly* 

Cavities  on  the  labial  surface  near 
the  incisal,  present  the  greatest  dif- 
ficulties ;  the  surface  of  the  tooth  be- 
ing nearly  flat,  it  aflows  the  shadow 

90 


from  the  thin  layer  of  cement  to  meet 
the  eye  at  every  angle. 

Much  better  results  are  obtained 
with  the  gingival  cavities,  as  the 
tooth  at  that  point  has  sufficient 
curve  to  prevent  the  reflection  of  the 
cement  meeting  the  eye. 

Also,  the  thicker  the  inlay,  the  less 
is  the  shadow  effect. 

The  next  and  the  greatest  thing 
which  bears  on  this  question  is  the 
cement.  A  transparent  cement 
would  overcome  the  shadow  ques- 
tion, but  one  must  get  the  best  re- 
sults possible  with  the  cement  now 
available. 

An  inlay  that  exactly  fits  the  cav- 
ity, instead  of  being  the  thickness  of 
the  matrix  smaller,  gives  the  advan- 

91 


tagc  of  having  the  least  possible 
amount  of  cement  between  the  inlay 
and  the  toothy  as  the  greater  the 
amount  of  cement  the  heavier  the 
shadow.  Each  point  gained  in  this 
way  brings  this  problem  a  little 
nearer  solution. 

The  color  of  the  cement  is  an  im- 
portant factor  and  must  be  consider- 
ed; with  an  inlay  the  thickness  of 
the  matrix  smaller  than  the  cavity, 
the  line  of  cement  showing,  compels 
the  use  of  a  cement  that  harmonizes 
with  the  color  of  the  inlay.  Each 
time  the  color  of  the  cement  is 
changed  a  different  shadow  effect 
must  be  overcome,  and  this  fre- 
quently results  in  failure  in  what 
might  otherwise  have  been  success. 

92 


When  the  inlay  exactly  fits  the 
cavity^  it  admits  of  so  small  an 
amount  of  cement  that  a  certain 
color  can  be  used  for  all  inlays. 

White  is  preferable  as  it  gives  the 
minimum  shadow.  This  can  be 
overcome  by  making  the  inlay  about 
a  shade  lighter  than  the  tooth,  thus 
counteracting  the  shadow  cast  by 
the  cement. 


m 


93 


A 

A  WORD  IN  CONCLUSION 

brief  summary  of  important 
points  in  the  application  of 
this  system  of  porcelain  inlay^ 
is  appended  for  ready  refer- 
ence. It  will  enable  the  be- 
ginner to  feel  more  confident  of  his 
ground  and^  if  faithfully  adhered  to^ 
will  avoid  the  danger  of  failure  at  the 
start,  which  is  often  charged  to  a 
new  system,  when  it  is  more  justly 
attributable  to  the  newness  of  the 
practitioner* 

jfii  j^  tfr' 

Become  thoroughly  convefsant  with 
the  theory  and  practice  of  this  system 
before  attempting  to  put  it  into  operation* 

94 


Do  not  be  afraid  to  cut  away  the  tooth; 
it  will  be  replaced  with  a  similar  sub- 
stance. 

Leave  the  walls  of  the  cavity  at  all 
points  perpendicular  to  the  surface  of  the 
tooth. 

Do  not  allow  your  cement  impression 
to  stay  in  the  tooth  until  it  is  very  hard; 
it  will  not  be  easy  to  remove. 

In  matching  for  color  the  inlay  is  more 
likely  to  be  too  dark  than  too  light. 

Be  sure  to  grind  out  all  of  the  color  in 
the  tooth  not  desired. 

Do  not  place  too  much  body  in  the 
matrix  at  the  first  baking:  just  a  thin 
layer. 

The  foundation^  or  first  baking,  should 
be  baked  to  a  bright  glaze. 

To  overcome  the  difficulty  of  handling 

small  inlays  while  cementing  them  to 

place,  fasten  the  end  of  a  wooden  tooth 

pick  to  the  inlay  with  sticky   wax.    If 

S5 


the  cavity  is  nearly  round,  mark  the 
gingival  side  of  the  tooth  pick;  this  will 
be  a  sufficient  guide  to  insure  proper  plac- 
ing of  the  inlay* 

Roughen  the  under  surface  of  the  in- 
lay, and  the  inner  surface  of  the  cavity, 
so  the  cement  will  adhere. 

In  cementing  the  inlay  to  place,  use 
nearly  an  equal  amount  of  water  with 
the  liquid.    It  will  hasten  the  setting. 

Do  not  finish  off  the  inlay  before  the 
cement  is  hard. 

Do  not  use  a  coarse  stone  to  grind  the 
inlay. 

Scrupulous  and  exact  cleanliness  must 
be  observed  with  every  step. 

If  this  system  is  followed  closely,  it  will 
eliminate  much  of  the  personal  equation, 
and  will  enable  the  many  to  obtain  per- 
fectly satisfactory  results  with  porcelain 
iniay.  ^ 

96 


It  may  be  desirable  to  redtsce  a  com- 
plicated cavity  in  some  of  the  approximal^ 
to  a  simple  cavity  of  the  second  class, 
which  can  be  done  by  restoring  a  portion 
of  the  cavity  with  gold,  from  beneath. 

A  pure  mat  platinum,  similar  to  the 
mat  gold,  could  be  used  advantageously 
to  re-enforce  and  fill  in  a  tear  in  the 
matrix,  by  swaging  it  to  place  with 
mouldine. 

The  necessary  instruments  for  this  sys- 
tem, aret 

Chisels  Nos.  75,  76,  S.  S.  W. 

Flaggs'  Instrument  No.  33,  S.  S.  W. 

Burnisher  No*  34  small,  S.  S.  W. 

Gem  Points  Nos.  J3,  J4,  S.  S.  W. 

Gem  Cavity  No.  J,  S.  S.  W. 

Fissure  Finishing  Burs  Nos.  57,  58. 

Fissure  Bur  No.  57. 

Fear  Shaped  Bur  No.  {. 

Britton  Cement. 

Arkansas  Stone  Point  No.  5,  S.  S.  W. 

Hindoostan  Lathe  Stone,  2^^  by  5- (6  in* 
97 


Date  Due 

iJJlfso 

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RK551 
Peck 


PtK^f^^^mmy-usm:: 


Porcelain 


2002398443 


P33 

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